User manual

25 Chapter 3
3.3.5 Interrupt Triggering Edge Control
The interrupt can be triggered by a rising edge or a falling edge of the
interrupt signal, selectable by the value written in the “triggering edge
control” bit in the interrupt control register, as shown in following table.
3.3.6 Interrupt Flag Bit
The “interrupt flag” bit is a flag indicating the status of an interrupt. It is
a readable and writable bit. Read the bit’s value to find the status of the
interrupt; write “1” to this bit to clear the interrupt. This bit must be
cleared in the ISR to service the next incoming interrupt.
F01: pattern patch interrupt flag bit of port A0
F02: change of state interrupt flag bit of port B0
Fn: interrupt flag bit of port Cn (n = 0 ~ 3)
Table 3.4: Triggering edge control bit values
En (n = 0 ~ 3) Triggering edge of interrupt signal
1 Rising edge trigger
0 Falling edge trigger
Table 3.5: Interrupt flag bit values
F01, F02 and Fn (n = 0 ~ 3) Interrupt Status
Read 1 Interrupt exists
0No interrupt
Write 1 Clear interrupt
0Don’t care